This invention is directed to a field of color signature sensor used in process automation which performs color recognition of objects for the purposes of identification, sorting or matching.
In this invention reflected (or transmitted) light from an illuminated object (or process) is transmitted optically to a spectral dispersive element in the form of a concave diffraction grating. Spectrally dispersed light from the grating is focussed on a photodetector array which generates a spatially discretized analog signal representing the color signature of the object. The signal is then converted to digital form and sent to a microprocessor for processing. The sampled and digitized signal is a unique and complete description of the colored object being observed. Cross-correlation and mean-value statistics are used by the microprocessor for color recognition.